Single acting impact absorbing device

ABSTRACT

The single acting impact absorbing device is interposed between the underframe center sill and the sliding sill of a railway car and has a single acting cylinder housed in a square hydraulic fluid reservoir, a first head of which normally abuts stop faces on a key housing fixed to the underframe center sill and a first set of stop faces fixed to the inner walls of the sliding sill. A piston rod slidably projects through the first head and the housing and carries a movement limiting member on its outer end which normally abuts stop faces on the opposite end of the housing and a second set of stop faces on the sliding sill. A spring rod secured to the piston rod retains a spring acting between the second head and a follower at the outer end of the spring rod, the spring stressing both rods in tension. A tube adjacent the second head houses the spring and restrains it against lateral buckling in compression, and filling access to the reservoir is had through filler tubes having their lower ends opening to the outer face of the second head adjacent the spring tube. A piston fixed to the piston rod normally is held adjacent the second head, and when the railway car receives an impact it moves relatively toward the other head, expelling fluid from the cylinder into the reservoir through a decreasing number of flow restricting orifices.

United States Patent [1 Hawthorne Dec.4, 1973 1 SINGLE ACTING IMPACTABSORBING DEVICE [75] Inventor: Vaughn T. Hawthorne,

Mechanicsburg, Pa.

[7 3] Assignee: Keystone Industries, Inc., Chicago,

Ill.

22 Filed: Oct. 22, 1971 21 Appl. No.: 191,634

Related US. Application Data 7 [63] Continuation-impart of Ser. No.1,903, Dec. 17, 1969, abandoned, which is a continuation of Ser. No.710,196, March 4, 1968, abandoned.

[52] US. Cl 213/8, 213/43, 213/64,

, 213/69 [51] Int. Cl. B6lg 9/08 [58] Field of Search 213/8, 43, 223,62,

[57] ABSTRACT The single acting impact absorbing device is interposedbetween the underframe center sill and the sliding sill of a railway carand has a single acting cylinder housed in a square hydraulic fluidreservoir, a first head of which normally abuts stop faces on a keyhousing fixed to the underframe center sill and a first set of stopfaces fixed to the inner walls of the sliding sill. A piston rodslidably projects through the first head and the housing and carries amovement limiting member on its outer end which normally abuts stopfaces on the opposite end of the housing anda second set of stop faceson the sliding sill. A spring rod secured to the piston rod retains aspring acting between the second head and a follower at the outer end ofthe spring rod, the spring stressing both rods in tension. A tubeadjacent the second head houses the spring and restrains it againstlateral buckling in compression, and filling access to the reservoir ishad through filler tubes having their lower ends opening to the outerface of the second head adjacent the spring tube. A piston fixed to thepiston rod normally is held adjacent the second head, and when therailway car receives an impact it moves relatively toward the otherhead, expelling fluid from the cylinder into the reservoir through adecreasing number of flow restricting orifices.

28 Claims, 18 Drawing Figures 0 ed. a

PATENTEU DEC 4 I973 SHEET 2 BF 6 PATENTEU DEC 75 SHEET 5 BF 6 WNW QNN

PATENTEHUEE 41m SHEET 6 BF 6 mMN SINGLE ACTING IMPACT ABSORBING DEVICECROSS REFERENCE TO RELATED APPLICATIONS BRIEF SUMMARY OF THE INVENTIONImpact absorbing devices which are interposed between the underframecenter sill structure and the sliding sill structure of a railway carmust'be capable of absorbing impacts received at both ends of the car.They have frequently been of the double acting type, but

later designs have emphasized single acting cylinders for such devices.

It should be. recognized that impact absorbing de-' vices in order to beeffective should accommodate a motion of the sliding sill'within theunderframe center sill of up to twenty inches. In double acting unitsthe sliding sill travel must be accommodated for both directions withinthe cylinder, and this results in a substantially long unit. It alsorequires that the piston rod in normal conditionproject from thecylinder where it is customarily enclosed ina bellows. The long lengthof the unit claims its price in weight and extravolume of hydraulicfluid. The bellows presents a service problem because its constantflexing reduces its effective life. These units usually were filled fromthe top and had to be completely removed from the railway car toreplenish the hydraulic fluid and for servicing. The return springswhich are usually. external of the unit were mounted on guide tubes orhoused within the sliding sill to rub thereagainst and the excessiveabrasive wear caused a shortened spring life.

' isfactory condition for the lubrication of the rod as it the presentinvention;

Some of these drawbacks to double acting units were overcome in singleacting units, such as a reduction in length, weight, and volume ofhydraulic fluid needed. The piston rod still projected from the cylinderand had to be enclosed within a bellows. The piston rod acted incompression, and the external spring rubbed and wore against the wallsof the sliding sill or against a guide tube. Replenishment of fluid andservicing-the unit required its removal from the car.

The disadvantages and objectionable characteristics of the prior devicesare overcome by the single acting impact absorbing device of the presentinvention which has, among others, the following advantages:

.1. It requires only one stop means fixed to the underframe center sill.It is also possible to use a single stop means applied to the slidingsill, thus making possible easy installation in a railway car. The priorunits require either two piston stops or two keys.

2. It is so constructed and arranged to provide tension on the operatingor piston rod. Operating the piston rod in tension permits the rod tobeloaded to a higher stress and eliminates alignment problems inherentin prior single acting devices. 3. It requires no oil volumecompensating devices because there is equal or less displacement of oilbe hind the piston than in front of it..Other single acting unitsrequire some means of volume displacement.

4. It requires no bellows because the piston rod is normally within theunit. This also provides a more satpasses through the packing.

5. It incorporates means to allow the unit to be filled while in therailway car and to protect against overfill- 7 on its outside. Thespring is placed within a housing and guide tube rather than placing thetube inside the spring. This will appreciably increase spring life.

his, therefore, the principal object of the present invention to providea new and improved single'acting impact absorbing device having theforegoing advantages over the. priorart devices.

- 'Another object is to provide a new and improvedsin gle acting impactabsorbing device which is more compact, lighter in weight, and lesscostly to manufacture,

service, and maintain than the prior devices.

Other objects and advantages will become apparent from the followingdescription and from the drawings.

BRIEF DESCRIPTION oF THE FIGURES OF THE DRAWINGS FIG. 1 is alongitudinal sectional view through an im-. pact absorbing devicecomprising a FIG. 2 is an enlarged and broken sectional 'view ofportions of FIG. 1;

FIG. 3 is a transverse sectional view taken along' the line 33 of FIG.2;

FIG. 4 is anenlarged sectional view taken along. the

line 4-4 of FIG. 3;

FIG. 5 is an irregular transverse sectional view takenalong the line 55of FIG. -2; v

FIG. 6 is a fragmentary sectional view taken along the line 66 of FIG.5; a Y

FIG. 7 is a schematic sectional view on the same scale as FIG. 1,showing the parts in position while moving under impact from the right;

FIG. 8 is a view similar to FIG. 7, showing the parts in position whilemoving under impact from the left;

FIG. 9 is a longitudinal sectional viewwith' parts broken away. of asecond embodiment of the invention;

FIG. 10 is a sectional view taken along the line l0--l0 of FIG. 9;

FIG. 11 is a schematic sectional viewon the same scale as FIG. 9,showing the parts in position while moving under impact from the left;

FIG. 12 is a view similar to FIG. 1 1, showing the parts in positionwhile moving under impact from the right;

FIG. 13 is a transversesectional view taken along the line l3- l3 ofFIG. 9;

FIG. 14 is an enlarged and broken sectional view of portions of FIG. 10;FIG. 15 is an enlarged sectional view line l5l5 of FIG. 14;

FIG. 16 is anenlarged sectional view taken along the line l6--l6 0f FIG.14;

FIG. 17 is a fragmentary sectional the line l7'l7 of FIG. 16; and

' FIG. 18 is a development view of a portion of the structure shown inFIG. 14.

taken along the first embodiment of view taken along A first embodimentof an impact absorbing device of the present invention, indicatedgenerally by the reference character It), is shown in FIGS. 1 through 8and is mounted between center sill structure 12 of the underframe of arailway car and sliding sill structure 14, which is housed within thecenter sill l2 and-slides relative thereto upon impact from either endof the car. The sliding sill 14 carries at its opposite outer ends theconventional coupler and draft gear which are not shown.

As best seen in FIG. 3, both the center sill l2 and the sliding sill 14are open at their lower sides. The center sill 12 is formed by a pair ofside walls or outwardly facing wide channels 16 which areinterconnected. across their upper flanges by a plate 18 which forms thetop portion of the center sill 12.

The sliding sill 14 comprises an invertedchannel 20 which has side wallshaving a pair of sidewardly projecting flanges 22 extending the lengthof the sill l4 and on which it slides on the various cross members ofthe underframe in a manner well known in the art.

The impact absorbing device is housed within the sliding sill 14 but issupported on a support or frame 23 which depends from the underframecenter sill 12. The frame 23 comprises a pair of longitudinallyextending bars 24 which are welded to the'lower faces of the lowerflanges of the channels 16 and between which is mounted a subframe whichincludes longitudinally extending bars 26 which are secured by bolts 28to the bars 24. Transverse angle members 30 interconnect the bars 26,and the latter are further interconnected by a plate 32 which is weldedto the bars 26 and the angle members 30. To the upper surface of theplate 32 is welded a pair of pads 34 on which the flanges 22 of thesliding sill l4 slide.

Also mounted on the plate 32 is a stop means or key stop providinghousing 36 which comprises a pair of elongated and spaced side walls 38which upstand from the plate 32 and between which at their lowerportions extend spacers 40. The side walls 38 are interconnected attheir upper ends by a cover plate 42 bolted thereto. The side walls 38are provided at their opposite ends, and therefore at the opposite endsof the housing, with stop face providing wear pads 44 and 45. They andthe key stop housing 36 serve as the positioning unit for the impactabsorbing device 10 when the sills 12 and 14 are in their normal orneutral position.

The bars 24 and 26 extend outwardly away from their position below thehousing 36, and a plate 48 extends between the upper portions of thesebars which are further braced by transverse members 50. The plate 48 hasa wear pad 52 secured to its upper surface on which a portion of theimpact absorbing device slides, as will be described hereinafter. Thisstructure completes the impact supporting device frame 23, and it can beseen that it hangs from the center sill 12 of the underframe of therailway car.

As best seen in FIGS. 2 and 5, the impact absorbing device 10 includes areservoir 54, rectangular,specifi cally square, in cross section, whichis closed at its opposite ends by a first head 56 anda second and outer'head 58. The opposite ends of the reservoir are welded to the heads 56and 58 to provide a liquid tight unit.

Within the reservoir 54 is a coaxial cylinder which extends between theheads 56 and 58 and is appropriately held in recesses 62 and 64 in theheads 56 and 58,

respectively. It is not essential that the'cylinder 60 be welded to theheads, and it is properly angularly located with respect to thereservoir 54 by a dowel 66 in the head 58. Along its length the wall ofthe cylinder 60 v is formed with a plurality of fluid flow restrictingports or orifices 68, which communicate the interior of the cylinder 60with the surrounding reservoir, and through which fluid flows during thefunctioning of the impact absorbing device 10, as will be explainedhereinafter. Fluid flow between the interior of cylinder 60 and thesurrounding reservoir in a substantially less restricted fashion iseffected by means of passages 70 formed in the head 58 and around theend of the wall of the cylinder 60 (FIGS. 5 and 6). The cylinder 60 isalso formed with relatively large ports 72 at its end adjacent the head58 for the purpose of providing further relatively unrestricted flow offluid. These ports 72 are arranged in a position of about 22 W from thehorizontal and vertical diameters of the cylinder'as seen in FIG. 5, sothat under normal conditions the passages 70 and ports 72 will be belowthe liquid'level in the reservoir 54.

A piston 74 having a peripheral packing 76 slides within the'cylinder60, and when the relative motion of the piston 74 is to the left withrespectto cylinder 60, as seen in FIG. 2, fluid is forced under pressurethrough the orifices 68 into the reservoir 54 and is taken in throughthe passages 70 and ports 72 and through such orifices 68 as areuncovered to the right of the piston 74. It will be observed that as therelative motion of piston and cylinder approaches the head 56 fewer flowrestricting orifices 68 for the expulsion of liquid are available, andthe resistance to piston movement increases as a result thereof. Whenthe movement is in the opposite direction the passages 70 and ports 72provide a relatively unhampered passage for the flow of fluid from theinterior of the cylinder 60 to the reservoir 54, and therefore theresistance to movement is not as great. This is important in restoringthe unit to its neutral or normal position, which is that shown in FIGS.1

and 2. i i

The head 58 is formed with a pair of inwardly projecting bosses 78 (FIG.6) which are drilled axially at 82 to the outer face 80 of the head 58.The outer ends of the bores 82 are normally closed by removable plugs84. The bosses 78'are drilled radially at 86 to intercept the axialbores 82 and to receive the lower ends of upwardly extending pipes 88which are located in the reservoir 54 adjacent the head 58. The upperand open ends 90 of the pipes 88 are adjacent the upper wall of thereservoir 54 and above most of the orifices 68 and all of thepassageways 70 and ports 72. When it is desired to fill the reservoir orto replenish any of the fluid which may have leaked from the reservoir54, as will happen during normal use over a long time period, the plugs84 are removed and hydraulic fluid is pumped through one of the bores 82and pipes 88 to spill into the reservoir 54. When the reservoir isfilled to the desired level as measured by the open upper end 90 of theother pipe 88, hydraulic fluid will flow down the pipe and leak frointhe open bore 82 to signal that the reservoir is properly filled. Theplugs 84 are then replaced,

and the unit will have been serviced.

The piston 74 is fixedly secured, as by welding, to an elongated memberor piston rod 92 which extends outwardly through a projecting boss 94 onthe head 56 to extend completely through the stop providing housing 36as seen in FIG. 2. The piston rod is supported in the boss 94 and in thehead 56 by a bushing 96 andpacking 98 which is held in place by asuitable retaining ring assembly 100.

At its outer end the piston rod 92 extends through and is welded to anabutment or movement limiting member 102 which is square in transverseconfiguration and is provided with radial strengthening ribs 104.Because of its size and shape the member 102 is guided by the walls of'the sliding sill l4 and its rotation is prevented. The piston 74 andpiston rod assembly 92 are normally biased to the right as seen in thedrawings, and therefore inner face 106 of the movement limiting member102 bears against the stop faces of the pads 44 l which are carried onthe side walls 38' of the housing 36.

At the opposite end of the assembly of the reservoir- 54 and'cylinder 60is an elongated member or a spring rod 108. The rod 108 extends throughahollowboss 110 projecting outwardly of the head 58, and at its inner endthe rod 108 engages in a recess 112 in the end of the piston rod 92 andis welded thereto so that the combination of piston rod 92 and springrod 108 moves as a unit. The rod 108 is supported in the head 58 by abushing 114, packing 116, and'packing retaine assembly 118.

The spring rod 108 is provided at its outer end with a spring follower120 which is held or retained thereon by a nut 122 and a locking cotterpin 124 so that the spring follower cannot inadvertently come off theend of the rod 108. Confined between the head 58'and the spring follower120 is a restoring means in the form of a heavy duty compression spring126 which urges the spring follower 120 rightwardly as seen in FIGS. 1and 2, and thus tends to hold the piston 74 in the rightward position.The motion limiting member 102 is held against the stop providinghousing 36 and the assembly of the impact absorbing device is in itsneutral or normal position. Since this spring is under compression, therods92 and 108 are stressed in tension, which permits higher stresses inthe rod and requires no special structure for alignment or support.

The spring is enclosed within an elongated spring housing tube 128 whichis welded in a seat in the outer face of the head 58. As seen in FIG. 6,access to the filler bores 82 and tubes 88 is at the corners of the head58.and outside the tube 128. Te spring housing tube l28. does not needany additional support, and it limits lateral buckling of the spring asit is placed under maximum compression during the absorption of animpact from either end of the railway car. This prevents wear of thespring 126 against the rod 108 and on its inner section where thestresses are higher. Circumferential wear is limited to the outside,thus giving longer spring life than was obtained heretofore. The springhousing tube is provided with an access opening 130 so that inspectionmay be made of the spring which otherwise cannot be seen, as duringnormal operation of the device the spring follower 120 never leaves thetube 128. The spring may readily be removed from the outer and open endof the tube 128'by removing the cotter pin 124 and nut 122.

To complete the'functioning of the device, the sliding sill 14 carrieson its inner face two pairs of stop blocks 132 and 134, The stop blocks132 have striking'faces 136 and the blocks 134'have striking faces 138.It will be noted that the distance between the striking faces 136 and138 is the same as the distance between the I faces on the pads .44 and46 carried at the opposite ends of the'key housing 36. In normalposition, thereor faces of the upstanding walls of the sliding sill l4,

and to increase the weld areas between the blocks and the sill, thesewalls are slotted at '140, there being three slots for each of theblocks 132, 134.

The functioning of the impact absorbing device can be readilyappreciated from a comparison of FIGS. 1, 7 and 8. FIG. 1 shows the unit10 in is normal position with the movement limiting member 102 bearingagainst the left end of the housing 36 and against the stop blocks 132.The spring 126 also urges the cylinder 60 and reservoir 54 leftwardly sothat the head 56 bears against the right end of the housing 36 andagainst the stop blocks 134. The piston 74 is held adjacent the head 58and the greater portion of the piston rod 92 is within the cylinder 60.Since the housing 36 is carried by the underframe sill l2 and the blocks132, 134 are carried by the sliding sill, the sliding sill is centrallypositioned within the underframe center sill 12, and the couplers anddraft gear at the opposite ends of the sliding. sill project normallyfrom the car for the purpose of coupling.

Upon an impact from the right end of the car, which is illustrated in-FIG. 7, the sliding sill 14 is moved leftwardly and the blocks 132bearing against the movethe cylinder 60, fewer and fewer of the ports 68are available forthe expulsion of fluid. At the end of this '45 functionthe, spring 126 moves the spring follower 120 rightwardly and since itis mounted on the spring rod 108 which is fixed to the piston rod 92,the'piston 74 moves rightwardly in the cylinder 60, and the movementlimiting member pulls the sliding sill 14 rightwardly in the underframesill 12 to the normal or FIG. 1 position. I

The function is similar when the impact occurs from the left end of thecar and of the unit (FIG. 8), In this case the blocks 134, being inengagement withthe head 56, move the assembly of the cylinder andthe'reservoir 54 rightwardly so that the piston 74 is stationaryrelative to the underframe center sill 12, while the cylinderandreservoir move on the shelf plate 48 with the sliding sill 14. Themotion limiting member 102 is abutted against the left end of thehousing 36 and does not move relative to the under-frame sill l2, andthe stops 132 move away from the motion limiting member 102. Restorationis effected by the spring 126in the same general fashion, except in thiscasethe cylinder 60 and reservoir 54 are moved with the sliding sill 14.

. A second embodiment of an impact absorbing device I of the presentinvention, indicated generally by the ref .erence character 210, isshown in FIGS 9 through 18,

and is mounted between center sill structure 212 and sliding sillstructure 214 of a car. As best seen in FIG. 13, the center sill 212 isformed by wide channels 216 and a plate 218. The sliding sill 214comprises a channel 220 which has projecting flanges 222 on which itslides. The impact absorbing device 210 is supported on a frame 223which comprises bars 224 welded to the channels 216. The bars 226 aresecured by bolts 228 to the bars 224. Transverse angle members 230connect to the bars 226, as does a plate 232. The plate 232 has a pairof pads 234 on which the sliding sill 214 slides.

Also mounted on the plate 232 is a key stop providing housing 236 whichcomprises a pair of side walls 238 and between which extend spacers 240.The side walls 238 are connected at their upper ends by a cover plate242 and are provided at their sides or ends with stop faces providingwear pads 244 and 246 (FIG. 14). A plate 248 (FIG. 14), having braces250 and wear plates 253 extends between the upper portions of the bars224 and 226.

As best seen in FIGS. 13, 14, and 16, theimpact The piston 274 isfixedly secured, as by welding, to

. a piston rod 292 which extends at one end outwardly absorbing device210 includes a reservoir 254 having corner reinforcements 255 (FIG. 15)and closed at its ends by a first head 256 and a second and outer head258. Wear pads 252 are secured about the four sides of the reservoir254. A cylinder 260 extends between the fers from the embodiment 10 inthat there are no passages similar to passages 70. The cylinder 260 has,instead, many large ports 272 (FIGS. 14, 15 and 16) at its end adjacentthe head 258. The ports 272 are arranged about the periphery of thecylinder. A layout of the ports 268 and 272 is shown in FIG. 18.

A piston 274 having packing 276 (FIG. 14) slides within the cylinder260. When the piston 274 moves to the left in the cylinder 260, fluid isforced under pressure through the orifices 268 into the reservoir 254and is taken in through the ports 272 and through such orifices 268 asare uncovered to the right of the piston 274. When the movement is inthe opposite direction the ports 272 provide a relatively unhamperedpassage for the flow of fluid from the interior of the cylinder 260 tothe reservoir 254.

The fluid filling means of the device 210 is constructed differentlyfrom that of device 10. In head 258 are openings 282 (FIGS. 16 and 17)which are located at the comers of the outer face 280 of the head 258.The outer ends of the openings 282 are normally closed by removableplugs 284. The inner ends of the openings 282 are closed by adapterplugs283 which are welded to the head 258 and have axial openings 285 andradial openings 286. The openings 285 and 286 provide communicationbetween the openings 282 and an upwardly extending pipe 288 which fitswithin the openings 286 and is located in the reservoir 254 adjacent thehead 258. The tubes 288 are pinched or squeezed. as indicated at 291, toclear the cylinder 260. To fill the reservoir 254, a similar procedureis followed as was described for device 10. A pipe plug 289 (FIG. 16) isprovided for initially filling the cylinder and reservoir.

through a projecting boss 294 on the head 256 to ex-' tend through thehousing 236, as seen in FIG. 14. The piston rod is supported by abushing 296 and packing 298 which is retained by a ring assembly 300.The piston rod 292 is welded to a movement limiting member 302 havingstrengthening ribs 304. The piston 274 and piston rod assembly 292 arenormally biased to the right, and the inner face 306 (FIG. 14) of themovement limiting member 302 bears against the stop faces of the pads244 on the side walls 238 of the housing 236.

Unlike the piston rod 92, the piston rod 292 extends through both headsof the cylinder 260, and at the other end extends through a hollow boss310 (FIG. 14) of the head 258. A spring rod 308 at its-inner end engagesin a recess 312 in the other end of the piston rod 292 and is weldedthereto. The rod 292 is supported in the head 258 by a bushing 314,packing 316, and packing retainer assembly 318.

Unlike the spring rod 108, the spring rod 308 is provided at its outerend with a three piece split bushing 321 which has a flange which abutsa spring follower 320. A washer 322 is welded to the end of the rod 308and retains the bushing 321 and thespring follower 320 on the rod 308.Confined between a spring seat ring 325 adjacent the head 258 and thespring follower 320 is a heavy duty compression spring 326 which urgesthe spring follower 320 rightwardly as seen in FIGS. 9 and 14. Sincethis spring is under compression, the rods 292 and 308 are stressed intension. The spring is enclosed within a spring housing tube 328 whichis welded at one end to the spring seat 325. As seen in FIG. 16, accessstill is provided to the filler bores 282. The spring housing tube 328limits lateral buckling of the spring during the absorption of an impactfrom either end of the railway car. The spring housing tube may beprovided with an access opening so that inspection may be made of thespring. The spring may be removed from the outer and open end of the.tube 328 by compressing the spring 326 and removing the split bushing321, the spring follower 320 then being slid over the washer 322. Thenboth the spring 326 and the tube 328 can be removed.

The sliding sill 214 carries a pair of one piece stop blocks 332 and334. The stop blocks'332 and 334 have striking faces 336 at one end andstriking faces 338 at the other end. It will be noted that the distancebetween the striking faces 336 and 338 is the same as the distancebetween the faces on the pads 244 and 246 of the key housing 236. Innormal position, the face 306 of the motion limiting member 302 bearsagainst the stop faces 336 and the pads 244, and the outer face of thehead 256 bears against the stop faces 338 and pads 246 (FIG. 9). Theblocks 322, 334 are welded to the inner faces of the upstanding walls ofthe sliding'sill 214, and to increase the weld areas between the blocksand the sill, these walls are slotted at 340 (FIG. 14), there being fourslots for each of the blocks 332, 334.

The functioning of the impact absorbing device 210 is similar to that ofthe device 10. FIG. 9 shows the unit 210 in its normal position with themovement limiting member 302 bearing against the left end of the housing236 and against the faces 336 of the stop blocks 332 and 334. The spring326 also urges the cylinder 260 and reservoir 254 leftwardly so that thehead 256 bears sill 212.

against the right end-of the housing 236 and against the faces 33s ofthe stop blocks 332 and 334.The piston 274 is held adjacent the head258. Since the housing 236is carried by the underframe sill 212 and theblocks 32 334 are carried by the sliding sill 2l4,the sliding sill iscentrally positioned within the underframe center covered orifices 268.'The spring 326 returns the spring follower 320, the spring rod 308, thepiston rod 292,

and the piston 274 to the right, and the movement lim -iting-member 302pulls the sliding sill 2l4'rightwardly in the underframe sill 212 to thenormal or FIG. 9 position.

When the impact occurs from the left end of the car (FIG. 11 the'faces33s of the blocks 332 and 334 being in engagement with the head 256,move the cylinder 260 and the reservoir 254 rightwardly so that thepiston 274 is stationary relative to the under-frame center sill 212,while the cylinder and reservoir move on the shelf plate 248 with thesliding sill 214. The motion limiting member 302 is abutted against theleft end of the housing 236 and does not move relative to the underframesill 212, and the faces 336 of the blocks 332 and 334 move away from themotion limiting member 302. Restoration is effected by the spring 326 inthe same general fashion, except in this case the cylinder 260 andreservoir 254 are moved with the sliding sill 214. 1 From the foregoingdescription it will be seen thatthe objectives which are claimed forthis invention at the outset of this specification are obtained by theapparatus described.

1 claim:

opposite said first head member and the second of said sliding sillstops,

a spring rodsecured to said piston rod interiorly of said cylinder andslidably projecting through said se'cond head member and having a springfollower mounted 'on its outer end, and

a return spring encircling said spring rod and extending between saidsecond head and said follower to place said piston rod and said springrod under tension, I I

whereby said spring tends to hold said piston in that end of saidcylinder adjacent said second head member, said first'head memberagainst said key 1, wherein said key stop means comprises a key stophousingthrough which said piston rod extends, said housing being carriedon the underframe center sill and l. A single acting impact absorbingdevice for installation in interposition between the underframe centertween said head members, and having fluid flow restricting orificesthroughout the length of its wall to communicate the interior of thecylinder with said reservoir, means at said secondhead interconnectingthe interior of said cylinder and said reservoir for relatively freeflow of fluid, I

a piston slidably positioned within said cylinder,

a piston rod secured-to said'piston'and extending through said firsthead and past said key stop means,

a movement limiting member carried by said piston rod at the outer endto abut said, key stop means projecting into the sliding sill.

3. An impact absorbing device as set forth in claim i 2, wherein saidkey stop housing is mounted on a frame carried by the underframe centersill, and said fluid reservoiris slidably mounted on aportion of saidframe.

4. An impact absorbing device as set forth in claim 2, wherein said keystop housinghas pairs of stop faces at its opposite ends-and said firsthead member normally abuts one of said pairs-of stop faces.

5. An impact absorbingdevice as set forth in claim 1, wherein said twosliding sill stops comprise two sets of such stops and said first headmember normally abuts the first of said sets of stops.

6. An impact absorbing device as set forth in claim 5, wherein thesliding sill comprises an inverted channel and said two sets of slidingsill stops comprise two. pairs of stop blocks welded to the inner facesof the side walls of the channel. 7

7. An impact absorbing device as set forth in claim 1, wherein saidmeans providing relatively free flow of fluid between said cylinder andsaid reservoir includes a plurality of passages in "said second headmember around the end of said cylinder.

8. An impact absorbing device as claimed in claim 7, wherein said meansproviding relatively free flow of fluid between said cylinder and saidreservoir additionally includes a plurality of free flow ports in saidcylinder adjacent said second head member.

9. An impact absorbing device as claimed in claim 1, including a springhousing tube carried by said second head and enclosing said spring, saidrod and said foll'ower. j

10. An impact absorbing device as claimed in claim .9, wherein the outerend of said tubeis open and addiond head member for filling'saidreservoir.

12. An impact absorbing device as claimed in claim 11, wherein saidreservoir filling means comprises a normally closed filling opening insaid second head member, and means forming a fluid passage having oneend at said opening and its other end adjacent the upper portion of saidreservoir.

13. An impact absorbing device as claimed in claim 11, wherein saidreservoir filling means comprises a pair of bosses on said second headmember projecting into said reservoir at the lower corners thereof,normally closed bores in said bosses openablc to the exterior face ofsaid second head member, and a pair of tubes mounted in said bossescommunicating with said bores and extending upwardly alongside saidcylinder with their upper ends open adjacent the upper portion of saidreservoir, whereby when fluid is introduced into said reservoir throughone of said tubes the other tube serves as an indicator that thereservoir is filled to a predetermined level.

14. A single acting impact absorbing device for installation ininterposition between the underframe center sill and the sliding sill ofa railway car, comprising in combination,

a key stop housing carried by the underframe center sill and projectinginto the sliding sill and having pairs of stop faces at itsopposite'ends,

two sets of stops carried on the interior of the sliding sill andlongitudinally spaced distances equal to the distance between said keystop faces at the opposite ends of said housing,

a fluid reservoir having first and second head members mounted withinthe sliding'sill and slidably supported on a shelf extending in onedirection away from said housing,

said first head member normally having its outer face abutting one ofsaid pairs of key stop faces on said housing and one of said sets ofsliding sill stops,.

means in said second head member for filling said reservoir withhydraulic fluid to a predetermined level and for indicating when thefluid has been filled to such level,

a cylinder housed within said reservoir, extending between said headmembers, and having fluid flow restricting orifices throughout thelengthof its wall to communicate the interior of the cylinder with saidreservoir,

relatively free flow passages in said second head member interconnectingthe interior of said cylinder and said reservoir,

relatively free flow ports in said cylinder adjacent said second headmember,

a piston slidably positioned within said cylinder,

a piston rod secured to said piston and extending through said firsthead member and through said key stop housing,

a movement limiting member carried by said piston rod exteriorly of saidkey step housing and abutting against the other of said pairs of stopfaces on said 12 a spring housing tube carried by said second head andenclosing said spring, said rod and said follower, whereby said springtends to hold said piston in that end of said cylinder adjacent saidsecond head member, said first head member against said one pair of saidkey stop faces on said housing and said first of said sets of slidingsill stops, and said move ment limiting member against said other pairof key stop faces on said housing and said second of said sets ofsliding sill stops. 15. In a cushioned underframe railway car having anunderframe structure, an elongated sliding sill structure longitudinallymovable. relative to said underframe structure, and a hydrauliccushioning unit coacting between said structures for cushioning impactforces imposed against either -end of said sill structure, theimprovement comprising in combination:

a longitudinally extending support rigidly affixed to one of saidstructures, first stop means ridigly secured to said underframestructure and extending into said sliding sill structure,

said hydraulic cushioning unit including a piston and cylinder disposedwithin said sliding sill structure, said cylinder being slidably carriedon said support,

a piston rod extending from one end of said unit and carrying anabutment at its outer end,

restoring means disposed at the opposite end of said unit andoperatively coacting betweensaid piston and said cylinder for normallyurging said unit in one direction so that said one end of said unitnormally engages said first stop means and also urging said abutment inthe opposite direction into engagement with said first stop means, and

second stop means rigid with said sliding sill structure and engageablewith said abutment and said one end of said unit for effecting relativemovement between said piston and said cylinder in response to an impactat either end of said sliding sill structure.

16. The structure of claim 15 further characterized in' that saidsupport is rigidly affixed to said underframe structure, and saidsupport has said first stop means rigidly secured to one portion of saidsupport and carries said cylinder on another portion of said support.

17. The structure of claim 15 further characterized in that saidrestoring means comprises an elongated member connected to said pistonand extending from the opposite end of said unit, a retainer mounted atthe outer end of' said elongated member, and a spring en circling saidelongated member and coacting between said retainer and said oppositeend of said unit.

18. The structure of claim 17 further characterized by the provision ofan elongated tubular housing surrounding said spring and engaging saidopposite end of said unit.

19. The structure of claim 15 further characterized in that saidunderframe structure comprises a fixed center sill having spaced sidewalls, said sliding sill structure comprises ,a movable sill with spacedside walls disposed between the side walls of said fixed center sill,and said support is rigidly connected to said fixed center sill andextends between the lower edges of the side walls thereof, said firststop means extending rigidly from said support between the side walls ofsaid movable sill, and said second stop means being rigidly secured tothe inner surfaces of the side wallsof said movable sill.. v

20. The structure of claim 19 further characterized in that said firststop means comprises a pair of elongated spaced wall portions, saidpiston rod extending between said wall portions, said abutment normallyengaging the outer ends of said wall portions and said one end of saidunit normally engaging the opposite ends of said wall portions. 1

21. The structure of claim 15 further characterized in that saidhydraulic cushioning unit includes a fluid reservoir, said cylinderbeing housed within and spaced from said reservoir, said piston beingdisposed within disposed inv the lower portion of the reservoir,removable closures in said openings, a pair of tubes communi eating withsaid openings and extending upwardly within said reservoir and havingopen upper ends disposed in the upper portion of said reservoir, wherebysaid reservoiris adapted to be filled with fluid by introduction offluid through one of said openings and its associated tube until thefluid flows out through the other of said tubes and the other of saidopenings.

24. The structure of claim 23 further characterized in that saidreservoir and said head members have a generally rectangularcross-section and said cylinder has a generally circular cross-section,said openings being provided adjacent the lower corner portions of thehead member at said opposite end of said unit and 25. An impactabsorbing device for a railway car comprising, in combination:

a longitudinally extending support,

first stop means rigidly mounted on one portion of cylinder, saidcylinder being slidably carried on another portion of said support, apiston rod extending from one end of said unit and carrying an abutmentat its outer end, restoring means disposed at the opposite end of saidunit and operatively coacting between said piston and said cylinder fornormally urging said unit in one direction with said one end of saidunit normally engaging said first stop means, said restoring means alsourging said abutment in the opposite direction into engagement with saidfirst stop means,

second stop means engageable with said abutment and said one end of saidunit for effecting relative movement between said piston and .saidcylinder in response to an impact. at either end of the device. 26. Thestructure of claim 25 further characterized in that said restoring meanscomprises an elongated member connected to said-piston and extendingfrom the opposite end of said unit, a retainer mounted at the outer endof said elongated member, and a spring encircling said elongated memberand coacting between said retainer and said opposite end of said unit.

27. The structure of claim 26 further characterized by the provision ofan elongated tubular housing surrounding said spring and engaging saidopposite end of I said unit.

being accessible externally of the head member and being incommunication with the space between said cylinder and said reservoir.

- support.

iss

28. The structure of claim 25 further characterized in that saidhydraulic cushioning unit includes a fluid reservoir, said cylinderbeing housed within and spaced from said reservoir, said piston beingdisposed within said cylinder, and said reservoir being slidable on said

1. A single acting impact absorbing device for installation ininterposition between the underframe center sill and the sliding sill ofa railway car, comprising in combination, key stop means carried by theunderframe center sill, two stops carried by the sliding sill, a fluidreservoir having first and second head members and longitudinallymovably mounted within the sliding sill, said first head member normallyhaving its outer face abutting said key stop means and one of saidsliding sill stops, a cylinder housed within said reservoir, extendingbetween said head members, and having fluId flow restricting orificesthroughout the length of its wall to communicate the interior of thecylinder with said reservoir, means at said second head interconnectingthe interior of said cylinder and said reservoir for relatively freeflow of fluid, a piston slidably positioned within said cylinder, apiston rod secured to said piston and extending through said first headand past said key stop means, a movement limiting member carried by saidpiston rod at the outer end to abut said key stop means opposite saidfirst head member and the second of said sliding sill stops, a springrod secured to said piston rod interiorly of said cylinder and slidablyprojecting through said second head member and having a spring followermounted on its outer end, and a return spring encircling said spring rodand extending between said second head and said follower to place saidpiston rod and said spring rod under tension, whereby said spring tendsto hold said piston in that end of said cylinder adjacent said secondhead member, said first head member against said key stop means and saidfirst of said sliding sill stops, and said movement limiting memberagainst said key stop means opposite said first head member and saidsecond of said sliding sill stops.
 2. An impact absorbing device as setforth in claim 1, wherein said key stop means comprises a key stophousing through which said piston rod extends, said housing beingcarried on the underframe center sill and projecting into the slidingsill.
 3. An impact absorbing device as set forth in claim 2, whereinsaid key stop housing is mounted on a frame carried by the underframecenter sill, and said fluid reservoir is slidably mounted on a portionof said frame.
 4. An impact absorbing device as set forth in claim 2,wherein said key stop housing has pairs of stop faces at its oppositeends and said first head member normally abuts one of said pairs of stopfaces.
 5. An impact absorbing device as set forth in claim 1, whereinsaid two sliding sill stops comprise two sets of such stops and saidfirst head member normally abuts the first of said sets of stops.
 6. Animpact absorbing device as set forth in claim 5, wherein the slidingsill comprises an inverted channel and said two sets of sliding sillstops comprise two pairs of stop blocks welded to the inner faces of theside walls of the channel.
 7. An impact absorbing device as set forth inclaim 1, wherein said means providing relatively free flow of fluidbetween said cylinder and said reservoir includes a plurality ofpassages in said second head member around the end of said cylinder. 8.An impact absorbing device as claimed in claim 7, wherein said meansproviding relatively free flow of fluid between said cylinder and saidreservoir additionally includes a plurality of free flow ports in saidcylinder adjacent said second head member.
 9. An impact absorbing deviceas claimed in claim 1, including a spring housing tube carried by saidsecond head and enclosing said spring, said rod and said follower. 10.An impact absorbing device as claimed in claim 9, wherein the outer endof said tube is open and additional means are provided in said tube formaintaining and servicing said spring.
 11. An impact absorbing device asclaimed in claim 1, wherein said reservoir is rectangular in crosssection and includes means adjacent the lower edge of said second headmember and accessible externally of said second head member for fillingsaid reservoir.
 12. An impact absorbing device as claimed in claim 11,wherein said reservoir filling means comprises a normally closed fillingopening in said second head member, and means forming a fluid passagehaving one end at said opening and its other end adjacent the upperportion of said reservoir.
 13. An impact absorbing device as claimed inclaim 11, wherein said reservoir filling means comprises a pair ofbosses on said second head member projecting into said reservoir at thelower cOrners thereof, normally closed bores in said bosses openable tothe exterior face of said second head member, and a pair of tubesmounted in said bosses communicating with said bores and extendingupwardly alongside said cylinder with their upper ends open adjacent theupper portion of said reservoir, whereby when fluid is introduced intosaid reservoir through one of said tubes the other tube serves as anindicator that the reservoir is filled to a predetermined level.
 14. Asingle acting impact absorbing device for installation in interpositionbetween the underframe center sill and the sliding sill of a railwaycar, comprising in combination, a key stop housing carried by theunderframe center sill and projecting into the sliding sill and havingpairs of stop faces at its opposite ends, two sets of stops carried onthe interior of the sliding sill and longitudinally spaced distancesequal to the distance between said key stop faces at the opposite endsof said housing, a fluid reservoir having first and second head membersmounted within the sliding sill and slidably supported on a shelfextending in one direction away from said housing, said first headmember normally having its outer face abutting one of said pairs of keystop faces on said housing and one of said sets of sliding sill stops,means in said second head member for filling said reservoir withhydraulic fluid to a predetermined level and for indicating when thefluid has been filled to such level, a cylinder housed within saidreservoir, extending between said head members, and having fluid flowrestricting orifices throughout the length of its wall to communicatethe interior of the cylinder with said reservoir, relatively free flowpassages in said second head member interconnecting the interior of saidcylinder and said reservoir, relatively free flow ports in said cylinderadjacent said second head member, a piston slidably positioned withinsaid cylinder, a piston rod secured to said piston and extending throughsaid first head member and through said key stop housing, a movementlimiting member carried by said piston rod exteriorly of said key stophousing and abutting against the other of said pairs of stop faces onsaid housing and the second of said sets of sliding sill stops, a springrod secured to said piston rod interiorly of said cylinder and slidablyprojecting through said second head, a spring follower mounted on theouter end of said spring rod, a return spring encircling said spring rodand extending between said second head and said follower and stressingsaid piston rod and said spring rod in tension, and a spring housingtube carried by said second head and enclosing said spring, said rod andsaid follower, whereby said spring tends to hold said piston in that endof said cylinder adjacent said second head member, said first headmember against said one pair of said key stop faces on said housing andsaid first of said sets of sliding sill stops, and said movementlimiting member against said other pair of key stop faces on saidhousing and said second of said sets of sliding sill stops.
 15. In acushioned underframe railway car having an underframe structure, anelongated sliding sill structure longitudinally movable relative to saidunderframe structure, and a hydraulic cushioning unit coacting betweensaid structures for cushioning impact forces imposed against either endof said sill structure, the improvement comprising in combination: alongitudinally extending support rigidly affixed to one of saidstructures, first stop means ridigly secured to said underframestructure and extending into said sliding sill structure, said hydrauliccushioning unit including a piston and cylinder disposed within saidsliding sill structure, said cylinder being slidably carried on saidsupport, a piston rod extending from one end of said unit and carryingan abutment at its outer end, restoring means disposed at the oppositeend of said unit and operatively coacting between said piston and saidcylinder for normally urging said unit in one direction so that said oneend of said unit normally engages said first stop means and also urgingsaid abutment in the opposite direction into engagement with said firststop means, and second stop means rigid with said sliding sill structureand engageable with said abutment and said one end of said unit foreffecting relative movement between said piston and said cylinder inresponse to an impact at either end of said sliding sill structure. 16.The structure of claim 15 further characterized in that said support isrigidly affixed to said underframe structure, and said support has saidfirst stop means rigidly secured to one portion of said support andcarries said cylinder on another portion of said support.
 17. Thestructure of claim 15 further characterized in that said restoring meanscomprises an elongated member connected to said piston and extendingfrom the opposite end of said unit, a retainer mounted at the outer endof said elongated member, and a spring encircling said elongated memberand coacting between said retainer and said opposite end of said unit.18. The structure of claim 17 further characterized by the provision ofan elongated tubular housing surrounding said spring and engaging saidopposite end of said unit.
 19. The structure of claim 15 furthercharacterized in that said underframe structure comprises a fixed centersill having spaced side walls, said sliding sill structure comprises amovable sill with spaced side walls disposed between the side walls ofsaid fixed center sill, and said support is rigidly connected to saidfixed center sill and extends between the lower edges of the side wallsthereof, said first stop means extending rigidly from said supportbetween the side walls of said movable sill, and said second stop meansbeing rigidly secured to the inner surfaces of the side walls of saidmovable sill.
 20. The structure of claim 19 further characterized inthat said first stop means comprises a pair of elongated spaced wallportions, said piston rod extending between said wall portions, saidabutment normally engaging the outer ends of said wall portions and saidone end of said unit normally engaging the opposite ends of said wallportions.
 21. The structure of claim 15 further characterized in thatsaid hydraulic cushioning unit includes a fluid reservoir, said cylinderbeing housed within and spaced from said reservoir, said piston beingdisposed within said cylinder, and said reservoir being slidable on saidsupport.
 22. The structure of claim 21 further characterized in thatsaid unit is provided at said opposite end thereof with means forfilling the reservoir with fluid.
 23. The structure of claim 22 furthercharacterized in that said unit comprises a pair of head members at theends of said unit, the head member at said opposite end of said unitbeing provided with a pair of openings disposed in the lower portion ofthe reservoir, removable closures in said openings, a pair of tubescommunicating with said openings and extending upwardly within saidreservoir and having open upper ends disposed in the upper portion ofsaid reservoir, whereby said reservoir is adapted to be filled withfluid by introduction of fluid through one of said openings and itsassociated tube until the fluid flows out through the other of saidtubes and the other of said openings.
 24. The structure of claim 23further characterized in that said reservoir and said head members havea generally rectangular cross-section and said cylinder has a generallycircular cross-section, said openings being provided adjacent the lowercorner portions of the head member at said opposite end of said unit andbeing accessible externally of the head member and being incommunication with the space between said cylinder and said reservoir.25. An impact absorbing device for a railway car Comprising, incombination: a longitudinally extending support, first stop meansrigidly mounted on one portion of said support, a hydraulic cushioningunit including a piston and cylinder, said cylinder being slidablycarried on another portion of said support, a piston rod extending fromone end of said unit and carrying an abutment at its outer end,restoring means disposed at the opposite end of said unit andoperatively coacting between said piston and said cylinder for normallyurging said unit in one direction with said one end of said unitnormally engaging said first stop means, said restoring means alsourging said abutment in the opposite direction into engagement with saidfirst stop means, and second stop means engageable with said abutmentand said one end of said unit for effecting relative movement betweensaid piston and said cylinder in response to an impact at either end ofthe device.
 26. The structure of claim 25 further characterized in thatsaid restoring means comprises an elongated member connected to saidpiston and extending from the opposite end of said unit, a retainermounted at the outer end of said elongated member, and a springencircling said elongated member and coacting between said retainer andsaid opposite end of said unit.
 27. The structure of claim 26 furthercharacterized by the provision of an elongated tubular housingsurrounding said spring and engaging said opposite end of said unit. 28.The structure of claim 25 further characterized in that said hydrauliccushioning unit includes a fluid reservoir, said cylinder being housedwithin and spaced from said reservoir, said piston being disposed withinsaid cylinder, and said reservoir being slidable on said support.